U.S. patent application number 09/854825 was filed with the patent office on 2002-01-17 for ink jet with rotary actuator.
Invention is credited to Silverbrook, Kia.
Application Number | 20020005877 09/854825 |
Document ID | / |
Family ID | 3802333 |
Filed Date | 2002-01-17 |
United States Patent
Application |
20020005877 |
Kind Code |
A1 |
Silverbrook, Kia |
January 17, 2002 |
Ink jet with rotary actuator
Abstract
An ink jet printer utilizing a rotary impeller mechanism to
eject ink drops is described. The nozzle chamber includes a number
of radial paddle wheel vanes; and a number of fixed paddles. Upon
rotation of the paddle wheel, ink within the paddle chambers is
pressurized, causing ink to be ejected from the ink ejection port.
The ink ejection port is located above a pivot point of the paddle
wheel and includes a wall which is located substantially on the
circumference of the paddle wheel. The rotation of the paddle wheel
is controlled by a thermal actuator which comprises an internal
electrically resistive element and an external jacket around the
resistive element, the jacket having a high coefficient of thermal
expansion and being constructed from polytetrafluoroethylene. The
thermal actuator undergoes circumferential expansion relative to
the paddle wheel.
Inventors: |
Silverbrook, Kia; (Balmain,
AU) |
Correspondence
Address: |
SILVERBROOK RESEARCH PTY LTD
393 DARLING STREET
BALMAIN
2041
AU
|
Family ID: |
3802333 |
Appl. No.: |
09/854825 |
Filed: |
May 14, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09854825 |
May 14, 2001 |
|
|
|
09112794 |
Jul 10, 1998 |
|
|
|
Current U.S.
Class: |
347/54 |
Current CPC
Class: |
B41J 2/1637 20130101;
B41J 2/1648 20130101; B41J 2/1642 20130101; B41J 2/1623 20130101;
B41J 2002/14346 20130101; B41J 2/16 20130101; B41J 2/14427
20130101; B41J 2/1639 20130101; B41J 2/14 20130101; B41J 2/1632
20130101; B41J 2/1626 20130101; B41J 2/17596 20130101 |
Class at
Publication: |
347/54 |
International
Class: |
B41J 002/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 15, 1997 |
AU |
PO8043 |
Claims
I claim:
1. An ink jet nozzle arrangement which comprises: a nozzle chamber
defining means which defines a chamber and which includes a wall
defining an ink ejection port; an ink ejecting device mounted in
the chamber to be rotatable through at least a predetermined arc of
rotation; and an actuator operatively arranged relative to the
device such that activation of the actuator causes rotation of the
device through at least said predetermined arc with rotation of the
device causing ejection of ink through the ink ejection port.
2. The arrangement of claim 1 in which at least one fixed
surface-defining element is arranged in the chamber and at least
one movable surface-defining element is carried by the device,
rotary displacement of the device at least through said
predetermined arc in an oscillatory manner causing, alternately,
ejection of ink from the ink ejection port and refilling of the
chamber with ink.
3. The arrangement of claim 2 which includes a plurality of
radially extending fixed surface defining elements with the device
carrying a corresponding number of movable surface-defining
elements, at least certain of the fixed surface-defining elements
having movable surface-defining elements associated with them.
4. The arrangement of claim 2 in which the actuator includes a
carrier, the device being mounted on the carrier.
5. The arrangement of claim 4 in which the actuator includes a
displacing means associated with the carrier for effecting
oscillatory displacement of the carrier.
6. The arrangement of claim 5 in which the displacing means
comprises a heater means which expands on being resistively
heated.
7. The arrangement of claim 6 in which the heater means is at least
partially embedded in a jacket, the jacket having a greater
coefficient of thermal expansion than the heater means so that any
expansion of the heater means is amplified by the jacket to
increase an arc of movement of the carrier and, accordingly, the
device.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation application of our
co-pending application Ser. No. 09/112,794 filed Jul. 10, 1998 and
which has been allowed. The disclosure of Ser. No. 09/112,794 is
specifically incorporated herein by reference.
[0002] The following Australian provisional patent applications are
hereby incorporated by cross-reference. For the purposes of
location and identification, U.S. patent applications identified by
their U.S. patent application Ser. Nos. (USSN) are listed alongside
the Australian applications from which the U.S. patent applications
claim the right of priority.
1 CROSS- REFERENCED AUSTRALIAN U.S. patent/patent application
PROVISIONAL (CLAIMING RIGHT OF PATENT PRIORITY FROM AUSTRALIAN
DOCKET APPLICATION NO. PROVISIONAL APPLICATION) NO. PO7991
09/113,060 ART01 PO8505 09/113,070 ART02 PO7988 09/113,073 ART03
PO9395 09/112,748 ART04 PO8017 09/112,747 ART06 PO8014 09/112,776
ART07 PO8025 09/112,750 ART08 PO8032 09/112,746 ART09 PO7999
09/112,743 ART10 PO7998 09/112,742 ART11 PO8031 09/112,741 ART12
PO8030 09/112,740 ART13 PO7997 09/112,739 ART15 PO7979 09/113,053
ART16 PO8015 09/112,738 ART17 PO7978 09/113,067 ART18 PO7982
09/113,063 ART19 PO7989 09/113,069 ART20 PO8019 09/112,744 ART21
PO7980 09/113,058 ART22 PO8018 09/112,777 ART24 PO7938 09/113,224
ART25 PO8016 09/112,804 ART26 PO8024 09/112,805 ART27 PO7940
09/113,072 ART28 PO7939 09/112,785 ART29 PO8501 09/112,797 ART30
PO8500 09/112,796 ART31 PO7987 09/113,071 ART32 PO8022 09/112,824
ART33 PO8497 09/113,090 ART34 PO8020 09/112,823 ART38 PO8023
09/113,222 ART39 PO8504 09/112,786 ART42 PO8000 09/113,051 ART43
PO7977 09/112,782 ART44 PO7934 09/113,056 ART45 PO7990 09/113,059
ART46 PO8499 09/113,091 ART47 PO8502 09/112,753 ART48 PO7981
09/113,055 ART50 PO7986 09/113,057 ART51 PO7983 09/113,054 ART52
PO8026 09/112,752 ART53 PO8027 09/112,759 ART54 PO8028 09/112,757
ART56 PO9394 09/112,758 ART57 PO9396 09/113,107 ART58 PO9397
09/112,829 ART59 PO9398 09/112,792 ART60 PO9399 6,106,147 ART61
PO9400 09/112,790 ART62 PO9401 09/112,789 ART63 PO9402 09/112,788
ART64 PO9403 09/112,795 ART65 PO9405 09/112,749 ART66 PP0959
09/112,784 ART68 PP1397 09/112,783 ART69 PP2370 09/112,781 DOT01
PP2371 09/113,052 DOT02 PP8003 09/112,834 Fluid01 PO8005 09/113,103
Fluid02 PO9404 09/113,101 Fluid03 PO8066 09/112,751 IJ01 PO8072
09/112,787 IJ02 PO8040 09/112,802 IJ03 PO8071 09/112,803 IJ04
PO8047 09/113,097 IJ05 PO8035 09/113,099 IJ06 PO8044 09/113,084
IJ07 PO8063 09/113,066 IJ08 PO8057 09/112,778 IJ09 PO8056
09/112,779 IJ10 PO8069 09/113,077 IJ11 PO8049 09/113,061 IJ12
PO8036 09/112,818 IJ13 PO8048 09/112,816 IJ14 PO8070 09/112,772
IJ15 PO8067 09/112,819 IJ16 PO8001 09/112,815 IJ17 PO8038
09/113,096 IJ18 PO8033 09/113,068 IJ19 PO8002 09/113,095 IJ20
PO8068 09/112,808 IJ21 PO8062 09/112,809 IJ22 PO8034 09/112,780
IJ23 PO8039 09/113,083 IJ24 PO8041 09/113,121 IJ25 PO8004
09/113,122 IJ26 PO8037 09/112,793 IJ27 PO8043 09/112,794 IJ28
PO8042 09/113,128 IJ29 PO8064 09/113,127 IJ30 PP9389 09/112,756
IJ31 PP9391 09/112,755 IJ32 PP0888 09/112,754 IJ33 PP0891
09/112,811 IJ34 PP0890 09/112,812 IJ35 PP0873 09/112,813 IJ36
PP0993 09/112,814 IJ37 PP0890 09/112,764 IJ38 PP1398 09/112,765
IJ39 PP2592 09/112,767 IJ40 PP2593 09/112,768 IJ41 PP3991
09/112,807 IJ42 PP3987 09/112,806 IJ43 PP3985 09/112,820 IJ44
PP3983 09/112,821 IJ45 PO7935 09/112,822 IJM01 PO7936 09/112,825
IJM02 PO7937 09/112,826 IJM03 PO8061 09/112,827 IJM04 PO8054
09/112,828 IJM05 PO8065 6,071,750 IJM06 PO8055 09/113,108 IJM07
PO8053 09/113,109 IJM08 PO8078 09/113,123 IJM09 PO7933 09/113,114
IJM10 PO7950 09/113,115 IJM11 PO7949 09/113,129 IJM12 PO8060
09/113,124 IJM13 PO8059 09/113,125 IJM14 PO8073 09/113,126 IJM15
PO8076 09/113,119 IJM16 PO8075 09/113,120 IJM17 PO8079 09/113,221
IJM18 PO8050 09/113,116 IJM19 PO8052 09/113,118 IJM20 PO7948
09/113,117 IJM21 PO7951 09/113,113 IJM22 PO8074 09/113,130 IJM23
PO7941 09/113,110 IJM24 PO8077 09/113,112 IJM25 PO8058 09/113,087
IJM26 PO8051 09/113,074 IJM27 PO8045 6,111,754 IJM28 PO7952
09/113,088 IJM29 PO8046 09/112,771 IJM30 PO9390 09/112,769 IJM31
PO9392 09/112,770 IJM32 PP0889 09/112,798 IJM35 PP0887 09/112,801
IJM36 PP0882 09/112,800 IJM37 PP0874 09/112,799 IJM38 PP1396
09/113,098 IJM39 PP3989 09/112,833 IJM40 PP2591 09/112,832 IJM41
PP3990 09/112,831 IJM42 PP3986 09/112,830 IJM43 PP3984 09/112,836
IJM44 PP3982 09/112,835 IJM45 PP0895 09/113,102 IR01 PP0870
09/113,106 IR02 PP0869 09/113,105 IR04 PP0887 09/113,104 IR05
PP0885 09/112,810 IR06 PP0884 09/112,766 IR10 PP0886 09/113,085
IR12 PP0871 09/113,086 IR13 PP0876 09/113,094 IR14 PP0877
09/112,760 IR16 PP0878 09/112,773 IR17 PP0879 09/112,774 IR18
PP0883 09/112,775 IR19 PP0880 09/112,745 IR20 PP0881 09/113,092
IR21 PO8006 6,087,638 MEMS02 PO8007 09/113,093 MEMS03 PO8008
09/113,062 MEMS04 PO8010 6,041,600 MEMS05 PO8011 09/113,082 MEMS06
PO7947 6,067,797 MEMS07 PO7944 09/113,080 MEMS09 PO7946 6,044,646
MEMS10 PO9393 09/113,065 MEMS11 PP0875 09/113,078 MEMS12 PP0894
09/113,075 MEMS13
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0003] Not applicable.
FIELD OF THE INVENTION
[0004] The present invention relates to ink jet printing and in
particular discloses a thermal elastic rotary impeller ink jet
printer.
[0005] The present invention further relates to the field of drop
on demand ink jet printing.
BACKGROUND OF THE INVENTION
[0006] Many different types of printing have been invented, a large
number of which are presently in use. The known forms of print have
a variety of methods for marking the print media with a relevant
marking media. Commonly used forms of printing include offset
printing, laser printing and copying devices, dot matrix type
impact printers, thermal paper printers, film recorders, thermal
wax printers, dye sublimation printers and ink jet printers both of
the drop on demand and continuous flow type. Each type of printer
has its own advantages and problems when considering cost, speed,
quality, reliability, simplicity of construction and operation
etc.
[0007] In recent years, the field of ink jet printing, wherein each
individual pixel of ink is derived from one or more ink nozzles has
become increasingly popular primarily due to its inexpensive and
versatile nature.
[0008] Many different techniques of ink jet printing have been
invented. For a survey of the field, reference is made to an
article by J Moore, "Non-Impact Printing: Introduction and
Historical Perspective", Output Hard Copy Devices, Editors R Dubeck
and S Sherr, pages 207 to 220 (1988).
[0009] Ink Jet printers themselves come in many different types.
The utilization of a continuous stream of ink in ink jet printing
appears to date back to at least 1929 wherein U.S. Pat. No.
1,941,001 by Hansell discloses a simple form of continuous stream
electro-static ink jet printing.
[0010] U.S. Pat. No. 3,596,275 by Sweet also discloses a process of
continuous ink jet printing including the step wherein the ink jet
stream is modulated by a high frequency electro-static field so as
to cause drop separation. This technique is still utilized by
several manufacturers including Elmjet and Scitex (see also U.S.
Pat. No. 3,373,437 by Sweet et al)
[0011] Piezoelectric ink jet printers are also one form of commonly
utilized ink jet printing device. Piezoelectric systems are
disclosed by Kyser et al. in U.S. Pat. No. 3,946,398 (1970) which
utilizes a diaphragm mode of operation, by Zolten in U.S. Pat. No.
3,683,212 (1970) which discloses a squeeze mode of operation of a
piezoelectric crystal, Stemme in U.S. Pat. No. 3,747,120 (1972)
which discloses a bend mode of piezoelectric operation, Howkins in
U.S. Pat. No. 4,459,601 which discloses a piezoelectric push mode
actuation of the ink jet stream and Fischbeck in U.S. Pat. No.
4,584,590 which discloses a shear mode type of piezoelectric
transducer element.
[0012] Recently, thermal ink jet printing has become an extremely
popular form of ink jet printing. The ink jet printing techniques
include those disclosed by Endo et al in GB 2007162 (1979) and
Vaught et al in U.S. Pat. No. 4,490,728. Both the aforementioned
references disclose ink jet printing techniques that rely upon the
activation of an electrothermal actuator which results in the
creation of a bubble in a constricted space, such as a nozzle,
which thereby causes the ejection of ink from an aperture connected
to the confined space onto a relevant print media. Printing devices
utilizing the electro-thermal actuator are manufactured by
manufacturers such as Canon and Hewlett Packard.
[0013] As can be seen from the foregoing, many different types of
printing technologies are available. Ideally, a printing technology
should have a number of desirable attributes. These include
inexpensive construction and operation, high speed operation, safe
and continuous long term operation etc. Each technology may have
its own advantages and disadvantages in the areas of cost, speed,
quality, reliability, power usage, simplicity of construction and
operation, durability and consumables.
SUMMARY OF THE INVENTION
[0014] It is an object of the present invention to provide an
alternative form of inkjet printing utilizing nozzles which include
a rotary impeller mechanism to eject ink drops.
[0015] In accordance with a first aspect of the present invention
an ink ejection nozzle arrangement is presented comprising an ink
chamber having an ink ejection port, a pivotally mounted paddle
wheel with a first plurality of radial paddle wheel vanes and a
second plurality of fixed paddle chambers each of which has a
corresponding one of the pivotally mounted paddle wheel vanes
defining a surface of the paddle chamber such that upon rotation of
the paddle wheel, ink within the paddle chambers is pressurized
resulting in the ejection of ink through the ejection port.
Further, the paddle chambers can include a side wall having a
radial component relative to the pivotally mounted paddle wheel.
Preferably, the ink ejection port is located above the pivot point
of the paddle wheel. The radial components of the paddle chamber's
side walls are located substantially on the circumference of the
pivotally mounted paddle wheel. Advantageously, the rotation of the
paddle wheel is controlled by a thermal actuator. The thermal
actuator comprises an internal electrically resistive element and
an external jacket around the resistive element, made of a material
having a high coefficient of thermal expansion relative to the
embedded resistive element. Further, the resistive element can be
of a substantially serpentine form, and preferably, the outer
jacket comprises substantially polytetrafluoroethylene. The thermal
actuator can undergo circumferential expansion relative to the
pivotally mounted paddle wheel.
[0016] In accordance with a second aspect of the present invention,
a method is provided to eject ink from an ink jet nozzle
interconnected to the ink chamber. The method comprises
construction of a series of paddle chambers within the ink chamber,
each of which has at least one moveable wall connected to a central
pivoting portion activated by an activation means. After
substantially filling the ink chamber with ink, utilisation of the
activation means connected to the moveable walls to reduce the
volume in the paddle chambers results in an increased ink pressure
within the chambers and consequential ejection of ink from the ink
jet nozzle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Notwithstanding any other forms which may fall within the
scope of the present invention, preferred forms of the invention
will now be described, by way of example only, with reference to
the accompanying drawings in which:
[0018] FIG. 1 is an exploded perspective view illustrating the
construction of a single ink jet nozzle arrangement in accordance
with a preferred embodiment of the present invention;
[0019] FIG. 2 is a plan view taken from above of relevant portions
of an ink jet nozzle arrangement in accordance with the preferred
embodiment;
[0020] FIG. 3 is a cross-sectional view through a single nozzle
arrangement, illustrating a drop being ejected out of the nozzle
aperture;
[0021] FIG. 4 provides a legend of the materials indicated in FIGS.
5 to 17; and
[0022] FIG. 5 to FIG. 17 illustrate sectional views of the
manufacturing steps in one form of construction of an ink jet
nozzle arrangement.
DESCRIPTION OF PREFERRED AND OTHER EMBODIMENTS
[0023] In the preferred embodiment, a thermal actuator is utilized
to activate a set of "vanes" so as to compress a volume of ink and
thereby force ink out of an ink nozzle.
[0024] The preferred embodiment fundamentally comprises a series of
vane chambers 2 which are normally filled with ink. The vane
chambers 2 include side walls which define static vanes 3 each
having a first radial wall 5 and a second circumferential wall 6. A
set of "impeller vanes" 7 is also provided which each have a
radially aligned surface and are attached to rings 9, 10 with the
inner ring 9 being pivotally mounted around a pivot unit 12. The
outer ring 10 is also rotatable about the pivot point 12 and is
interconnected with thermal actuators 13, 22. The thermal actuators
13, 22 are of a circumferential form and undergo expansion and
contraction thereby rotating the impeller vanes 7 towards the
radial wall 5 of the static vanes 3. As a consequence each vane
chamber 2 undergoes a rapid reduction in volume thereby resulting
in a substantial increase in pressure resulting in the expulsion of
ink from the chamber 2.
[0025] The static vane 3 is attached to a nozzle plate 15. The
nozzle plate 15 includes a nozzle rim 16 defining an aperture 14
into the vane chambers 2. The aperture 14 defined by rim 16 allows
for the ejection of ink from the vane chambers 2 onto the relevant
print media.
[0026] FIG. 2 shows a plan view taken from above of relevant
portions of an ink jet nozzle arrangement 1, constructed in
accordance with the preferred embodiment. The outer ring 10 is
interconnected at points 20, 21 to thermal actuators 13, 22. The
thermal actuators 13, 22 include inner resistive elements 24, 25
which are constructed from copper or the like. Copper has a low
coefficient of thermal expansion and is therefore constructed in a
serpentine manner, so as to allow for greater expansion in the
circumferential direction 28. The inner resistive elements 24, 25
are each encased in an outer jacket 26 of a material having a high
coefficient of thermal expansion. Suitable material includes
polytetrafluoroethylene (PTFE) which has a high coefficient of
thermal expansion (770.times.10.sup.-6). The thermal actuators 13,
22 is anchored at the points 27 to a lower layer of the wafer. The
anchor points 27 also form an electrical connection with a relevant
drive line of the lower layer. The resistive elements 24, 25 are
also electronically connected at 20, 21 to the outer ring 10. Upon
activation of the resistive element 24, 25, the outer jacket 26
undergoes rapid expansion which includes the expansion of the
serpentine resistive elements 24, 25. The rapid expansion and
subsequent contraction on de-energizing the resistive elements 24,
25 results in a rotational force in the direction 28 being induced
in the ring 10. The rotation of the ring 10 causes a corresponding
rotation in the relevant impeller vanes 7 (FIG. 1). Hence, by the
activation of the thermal actuators 13, 22, ink can be ejected out
of the nozzle aperture 14 (FIG. 1).
[0027] Turning now to FIG. 3, there is illustrated a
cross-sectional view through a single nozzle arrangement. The
illustration of FIG. 3 shows a drop 31 being ejected out of the
nozzle aperture 14 as a result of displacement of the impeller
vanes 7 (FIG. 1). The nozzle arrangement 1 is constructed on a
silicon wafer 33. Electronic drive circuitry 34 is first
constructed for control and driving of the thermal actuators 13,
22. A silicon dioxide layer 35 is provided for defining the nozzle
chamber which includes channel walls separating ink of one color
from adjacent ink reservoirs (not shown). The nozzle plate 15, is
also interconnected to the wafer 33 via nozzle plate posts, 37 so
as to provide for stable separation from the wafer 33. The static
vanes 3 are constructed from silicon nitrate as is the nozzle plate
15. The static vanes 3 and nozzle plate 15 can be constructed
utilizing a dual damascene process utilizing a sacrificial layer as
discussed further hereinafter.
[0028] One form of detailed manufacturing process which can be used
to fabricate monolithic ink jet printheads including a plane of the
nozzle arrangement 1 can proceed utilizing the following steps:
[0029] 1. Using a double sided polished wafer 33, complete drive
transistors, data distribution, and timing circuits using a 0.5
micron, one poly, 2 metal CMOS process 34. Relevant features of the
wafer at this step are shown in FIG. 5. For clarity, these diagrams
may not be to scale, and may not represent a cross section though
any single plane of the nozzle arrangement 1. FIG. 4 is a key to
representations of various materials in these manufacturing
diagrams, and those of other cross referenced ink jet
configurations.
[0030] 2. Deposit 1 micron of low stress nitride 35. This acts as a
barrier to prevent ink diffusion through the silicon dioxide of the
chip surface.
[0031] 3. Deposit 2 microns of sacrificial material 50.
[0032] 4. Etch the sacrificial layer using Mask 1. This mask
defines the axis pivot and the anchor points 12 of the actuators.
This step is shown in FIG. 6.
[0033] 5. Deposit 1 micron of PTFE 51.
[0034] 6. Etch the PTFE down to top level metal using Mask 2. This
mask defines the heater contact vias. This step is shown in FIG.
7.
[0035] 7. Deposit and pattern resist using Mask 3. This mask
defines the heater, the vane support wheel, and the axis pivot.
[0036] 8. Deposit 0.5 microns of gold 52 (or other heater material
with a low Young's modulus) and strip the resist. Steps 7 and 8
form a lift-off process. This step is shown in FIG. 8.
[0037] 9. Deposit 1 micron of PTFE 53.
[0038] 10. Etch both layers of PTFE down to the sacrificial
material using Mask 4. This mask defines the actuators and the bond
pads. This step is shown in FIG. 9.
[0039] 11. Wafer probe. All electrical connections are complete at
this point, and the chips are not yet separated.
[0040] 12. Deposit 10 microns of sacrificial material 55.
[0041] 13. Etch the sacrificial material down to heater material or
nitride using Mask 5. This mask defines the nozzle plate support
posts and the moving vanes, and the walls surrounding each ink
color. This step is shown in FIG. 10.
[0042] 14. Deposit a conformal layer of a mechanical material and
planarize to the level of the sacrificial layer. This material may
be PECVD glass, titanium nitride, or any other material which is
chemically inert, has reasonable strength, and has suitable
deposition and adhesion characteristics. This step is shown in FIG.
11.
[0043] 15. Deposit 0.5 microns of sacrificial material 56.
[0044] 16. Etch the sacrificial material to a depth of
approximately 1 micron above the heater material using Mask 6. This
mask defines the fixed vanes 3 and the nozzle plate support posts,
and the walls surrounding each ink color. As the depth of the etch
is not critical, it may be a simple timed etch.
[0045] 17. Deposit 3 microns of PECVD glass 58. This step is shown
in FIG. 12.
[0046] 18. Etch to a depth of 1 micron using Mask 7. This mask
defines the nozzle rim 16. This step is shown in FIG. 13.
[0047] 19. Etch down to the sacrificial layer using Mask 8. This
mask defines the nozzle 14 and the sacrificial etch access holes
17. This step is shown in FIG. 14.
[0048] 20. Back-etch completely through the silicon wafer (with,
for example, an ASE Advanced Silicon Etcher from Surface Technology
Systems) using Mask 9. This mask defines the ink inlets 60 which
are etched through the wafer. The wafer is also diced by this etch.
This step is shown in FIG. 15.
[0049] 21. Back-etch the CMOS oxide layers and subsequently
deposited nitride layers through to the sacrificial layer using the
back-etched silicon as a mask.
[0050] 22. Etch the sacrificial material. The nozzle chambers are
cleared, the actuators freed, and the chips are separated by this
etch. This step is shown in FIG. 16.
[0051] 23. Mount the printheads in their packaging, which may be a
molded plastic former incorporating ink channels which supply the
appropriate color ink to the ink inlets at the back of the
wafer.
[0052] 24. Connect the printheads to their interconnect systems.
For a low profile connection with minimum disruption of airflow,
TAB may be used. Wire bonding may also be used if the printer is to
be operated with sufficient clearance to the paper.
[0053] 25. Hydrophobize the front surface of the printheads.
[0054] 26. Fill the completed printheads with ink 61 and test them.
A filled nozzle is shown in FIG. 17.
[0055] It would be appreciated by a person skilled in the art that
numerous variations and/or modifications may be made to the present
invention as shown in the specific embodiment without departing
from the spirit or scope of the invention as broadly described. The
present embodiment is, therefore, to be considered in all respects
to be illustrative and not restrictive.
[0056] The presently disclosed ink jet printing technology is
potentially suited to a wide range of printing systems including:
color and monochrome office printers, short run digital printers,
high speed digital printers, offset press supplemental printers,
low cost scanning printers, high speed pagewidth printers, notebook
computers with in-built pagewidth printers, portable color and
monochrome printers, color and monochrome copiers, color and
monochrome facsimile machines, combined printer, facsimile and
copying machines, label printers, large format plotters, photograph
copiers, printers for digital photographic `minilabs`, video
printers, PHOTO CD (PHOTO CD is a registered trademark of the
Eastman Kodak Company) printers, portable printers for PDAs,
wallpaper printers, indoor sign printers, billboard printers,
fabric printers, camera printers and fault tolerant commercial
printer arrays.
[0057] Ink Jet Technologies
[0058] The embodiments of the invention use an ink jet printer type
device. Of course many different devices could be used. However
presently popular ink jet printing technologies are unlikely to be
suitable.
[0059] The most significant problem with thermal ink jet is power
consumption. This is approximately 100 times that required for high
speed, and stems from the energy-inefficient means of drop
ejection. This involves the rapid boiling of water to produce a
vapor bubble which expels the ink. Water has a very high heat
capacity, and must be superheated in thermal ink jet applications.
This leads to an efficiency of around 0.02%, from electricity input
to drop momentum (and increased surface area) out.
[0060] The most significant problem with piezoelectric ink jet is
size and cost. Piezoelectric crystals have a very small deflection
at reasonable drive voltages, and therefore require a large area
for each nozzle. Also, each piezoelectric actuator must be
connected to its drive circuit on a separate substrate. This is not
a significant problem at the current limit of around 300 nozzles
per printhead, but is a major impediment to the fabrication of
pagewidth printheads with 19,200 nozzles.
[0061] Ideally, the ink jet technologies used meet the stringent
requirements of in-camera digital color printing and other high
quality, high speed, low cost printing applications. To meet the
requirements of digital photography, new ink jet technologies have
been created. The target features include:
[0062] low power (less than 10 Watts)
[0063] high resolution capability (1,600 dpi or more)
[0064] photographic quality output
[0065] low manufacturing cost
[0066] small size (pagewidth times minimum cross section)
[0067] high speed (<2 seconds per page).
[0068] All of these features can be met or exceeded by the ink jet
systems described below with differing levels of difficulty.
Forty-five different ink jet technologies have been developed by
the Assignee to give a wide range of choices for high volume
manufacture. These technologies form part of separate applications
assigned to the present Assignee as set out in the table under the
heading Cross References to Related Applications.
[0069] The ink jet designs shown here are suitable for a wide range
of digital printing systems, from battery powered one-time use
digital cameras, through to desktop and network printers, and
through to commercial printing systems.
[0070] For ease of manufacture using standard process equipment,
the printhead is designed to be a monolithic 0.5 micron CMOS chip
with MEMS post processing. For color photographic applications, the
printhead is 100 mm long, with a width which depends upon the ink
jet type. The smallest printhead designed is IJ38, which is 0.35 mm
wide, giving a chip area of 35 square mm. The printheads each
contain 19,200 nozzles plus data and control circuitry.
[0071] Ink is supplied to the back of the printhead by injection
molded plastic ink channels. The molding requires 50 micron
features, which can be created using a lithographically
micromachined insert in a standard injection molding tool. Ink
flows through holes etched through the wafer to the nozzle chambers
fabricated on the front surface of the wafer. The printhead is
connected to the camera circuitry by tape automated bonding.
[0072] Tables of Drop-on-Demand Ink Jets
[0073] Eleven important characteristics of the fundamental
operation of individual ink jet nozzles have been identified. These
characteristics are largely orthogonal, and so can be elucidated as
an eleven dimensional matrix. Most of the eleven axes of this
matrix include entries developed by the present assignee.
[0074] The following tables form the axes of an eleven dimensional
table of ink jet types.
[0075] Actuator mechanism (18 types)
[0076] Basic operation mode (7 types)
[0077] Auxiliary mechanism (8 types)
[0078] Actuator amplification or modification method (17 types)
[0079] Actuator motion (19 types)
[0080] Nozzle refill method (4 types)
[0081] Method of restricting back-flow through inlet (10 types)
[0082] Nozzle clearing method (9 types)
[0083] Nozzle plate construction (9 types)
[0084] Drop ejection direction (5 types)
[0085] Ink type (7 types)
[0086] The complete eleven dimensional table represented by these
axes contains 36.9 billion possible configurations of ink jet
nozzle. While not all of the possible combinations result in a
viable ink jet technology, many million configurations are viable.
It is clearly impractical to elucidate all of the possible
configurations. Instead, certain ink jet types have been
investigated in detail. These are designated IJ01 to IJ45 above
which matches the docket numbers in the table under the heading
Cross References to Related Applications.
[0087] Other ink jet configurations can readily be derived from
these forty-five examples by substituting alternative
configurations along one or more of the 11 axes. Most of the IJ01
to IJ45 examples can be made into ink jet printheads with
characteristics superior to any currently available ink jet
technology.
[0088] Where there are prior art examples known to the inventor,
one or more of these examples are listed in the examples column of
the tables below. The IJ01 to IJ45 series are also listed in the
examples column. In some cases, print technology may be listed more
than once in a table, where it shares characteristics with more
than one entry.
[0089] Suitable applications for the ink jet technologies include:
Home printers, Office network printers, Short run digital printers,
Commercial print systems, Fabric printers, Pocket printers,
Internet WWW printers, Video printers, Medical imaging, Wide format
printers, Notebook PC printers, Fax machines, Industrial printing
systems, Photocopiers, Photographic minilabs etc.
[0090] The information associated with the aforementioned 11
dimensional matrix are set out in the following tables.
2 Description Advantages Disadvantages Examples ACTUATOR MECHANISM
(APPLIED ONLY TO SELECTED INK DROPS) Thermal An electrothermal
Large force High power Canon Bubblejet bubble heater heats the ink
to generated Ink carrier 1979 Endo et al GB above boiling point,
Simple limited to water patent 2,007,162 transferring significant
construction Low efficiency Xerox heater-in- heat to the aqueous No
moving parts High pit 1990 Hawkins et ink. A bubble Fast operation
temperatures al U.S. Pat. No. nucleates and quickly Small chip area
required 4,899,181 forms, expelling the required for actuator High
mechanical Hewlett-Packard ink. stress TIJ 1982 Vaught et The
efficiency of the Unusual al U.S. Pat. No. process is low, with
materials required 4,490,728 typically less than Large drive 0.05%
of the electrical transistors energy being Cavitation causes
transformed into actuator failure kinetic energy of the Kogation
reduces drop. bubble formation Large print heads are difficult to
fabricate Piezo- A piezoelectric crystal Low power Very large area
Kyser et al electric such as lead consumption required for actuator
U.S. Pat. No. lanthanum zirconate Many ink types Difficult to
3,946,398 (PZT) is electrically can be used integrate with Zoltan
U.S. Pat. No. activated, and either Fast operation electronics
3,683,212 expands, shears, or High efficiency High voltage 1973
Stemme bends to apply drive transistors U.S. Pat. No. pressure to
the ink, required 3,747,120 ejecting drops. Full pagewidth Epson
Stylus print heads Tektronix impractical due to IJ04 actuator size
Requires electrical poling in high field strengths during
manufacture Electro- An electric field is Low power Low maximum
Seiko Epson, strictive used to activate consumption strain (approx.
Usui et all JP electrostriction in Many ink types 0.01%) 253401/96
relaxor materials such can be used Large area IJ04 as lead
lanthanum Low thermal required for actuator zirconate titanate
expansion due to low strain (PLZT) or lead Electric field Response
speed magnesium niobate strength required is marginal (.about.10
(PMN). (approx. 3.5 V/.mu.m) .mu.s) can be generated High voltage
without difficulty drive transistors Does not require required
electrical poling Full pagewidth print heads impractical due to
actuator size Ferro- An electric field is Low power Difficult to
IJ04 electric used to induce a phase consumption integrate with
transition between the Many ink types electronics antiferroelectric
(AFE) can be used Unusual and ferroelectric (FE) Fast operation
materials such as phase. Perovskite (<1 .mu.s) PLZSnT are
materials such as tin Relatively high required modified lead
longitudinal strain Actuators require lanthanum zirconate High
efficiency a large area titanate (PLZSnT) Electric field exhibit
large strains of strength of around 3 up to 1% associated V/.mu.m
can be readily with the AFE to FE provided phase transition.
Electro- Conductive plates are Low power Difficult to IJ02, IJ04
static plates separated by a consumption operate electrostatic
compressible or fluid Many ink types devices in an dielectric
(usually air). can be used aqueous Upon application of a Fast
operation environment voltage, the plates The electrostatic attract
each other and actuator will displace ink, causing normally need to
be drop ejection. The separated from the conductive plates may ink
be in a comb or Very large area honeycomb structure, required to
achieve or stacked to increase high forces the surface area and
High voltage therefore the force. drive transistors may be required
Full pagewidth print heads are not competitive due to actuator size
Electro- A strong electric field Low current High voltage 1989
Saito et al, static pull is applied to the ink, consumption
required U.S. Pat. No. on ink whereupon Low temperature May be
damaged 4,799,068 electrostatic attraction by sparks due to air
1989 Miura et al, accelerates the ink breakdown U.S. Pat. No.
towards the print Required field 4,810,954 medium. strength
increases as Tone-jet the drop size decreases High voltage drive
transistors required Electrostatic field attracts dust Permanent An
electromagnet Low power Complex IJ07, IJ10 magnet directly attracts
a consumption fabrication electro- permanent magnet, Many ink types
Permanent magnetic displacing ink and can be used magnetic material
causing drop ejection. Fast operation such as Neodymium Rare earth
magnets High efficiency Iron Boron (NdFeB) with a field strength
Easy extension required. around 1 Tesla can be from single nozzles
High local used. Examples are: to pagewidth print currents required
Samarium Cobalt heads Copper (SaCo) and magnetic metalization
should materials in the be used for long neodymium iron boron
electromigration family (NdFeB, lifetime and low NdDyFeBNb,
resistivity NdDyFeB, etc) Pigmented inks are usually infeasible
Operating temperature limited to the Curie temperature (around 540
K) Soft A solenoid induced a Low power Complex IJ01, IJ05, IJ08,
magnetic magnetic field in a soft consumption fabrication IJ1O,
IJ12, IJ14, core electro- magnetic core or yoke Many ink types
Materials not IJ15, IJ17 magnetic fabricated from a can be used
usually present in a ferrous material such Fast operation CMOS fab
such as as electroplated iron High efficiency NiFe, CoNiFe, or
alloys such as CoNiFe Easy extension CoFe are required [1], CoFe,
or NiFe from single nozzles High local alloys. Typically, the to
pagewidth print currents required soft magnetic material heads
Copper is in two parts, which metalization should are normally held
be used for long apart by a spring. electromigration When the
solenoid is lifetime and low actuated, the two parts resistivity
attract, displacing the Electroplating is ink. required High
saturation flux density is required (2.0-2.1 T is achievable with
CoNiFe [1]) Lorenz The Lorenz force Low power Force acts as a IJ06,
IJ11, IJ13, force acting on a current consumption twisting motion
IJ16 carrying wire in a Many ink types Typically, only a magnetic
field is can be used quarter of the utilized. Fast operation
solenoid length This allows the High efficiency provides force in a
magnetic field to be Easy extension useful direction supplied
externally to from single nozzles High local the print head, for to
pagewidth print currents required example with rare heads Copper
earth permanent metalization should magnets. be used for long Only
the current electromigration carrying wire need be lifetime and low
fabricated on the print- resistivity head, simplifying Pigmented
inks materials are usually requirements. infeasible Magneto- The
actuator uses the Many ink types Force acts as a Fischenbeck,
striction giant magnetostrictive can be used twisting motion U.S.
Pat. No. effect of materials Fast operation Unusual IJ25 4,032,929
such as Terfenol-D (an Easy extension materials such as alloy of
terbium, from single nozzles Terfenol-D are dysprosium and iron to
pagewidth print required developed at the Naval heads High local
Ordnance Laboratory, High force is currents required hence
Ter-Fe-NOL). available Copper For best efficiency, the metalization
should actuator should be pre- be used for long stressed to approx.
8 electromigration MPa. lifetime and low resistivity Pre-stressing
may be required Surface Ink under positive Low power Requires
Silverbrook, EP tension pressure is held in a consumption
supplementary force 0771 658 A2 and reduction nozzle by surface
Simple to effect drop related patent tension. The surface
construction separation applications tension of the ink is No
unusual Requires special reduced below the materials required in
ink surfactants bubble threshold, fabrication Speed may be causing
the ink to High efficiency limited by surfactant egress from the
Easy extension properties nozzle. from single nozzles to pagewidth
print heads Viscosity The ink viscosity is Simple Requires
Silverbrook, EP reduction locally reduced to construction
supplementary force 0771 658 A2 and select which drops are No
unusual to effect drop related patent to be ejected. A materials
required in separation applications viscosity reduction can
fabrication Requires special be achieved Easy extension ink
viscosity electrothermally with from single nozzles properties most
inks, but special to pagewidth print High speed is inks can be
engineered heads difficult to achieve for a 100:1 viscosity
Requires reduction. oscillating ink pressure A high temperature
difference (typically 80 degrees) is required Acoustic An acoustic
wave is Can operate Complex drive 1993 Hadimioglu generated and
without a nozzle circuitry et al, EUP 550,192 focussed upon the
plate Complex 1993 Eirod et al, drop ejection region. fabrication
EUP 572,220 Low efficiency Poor control of drop position Poor
control of drop volume Thermo- An actuator which Low power
Efficient aqueous IJ03, IJ09, IJ17, elastic bend relies upon
differential consumption operation requires a IJ18, IJ19, IJ20,
actuator thermal expansion Many ink types thermal insulator on
IJ21, IJ22, IJ23, upon Joule heating is can be used the hot side
IJ24, IJ27, IJ28, used. Simple planar Corrosion IJ29, IJ30, IJ31,
fabrication prevention can be IJ32, IJ33, IJ34, Small chip area
difficult IJ35, IJ36, IJ37, required for each Pigmented inks IJ38,
IJ39, IJ40, actuator may be infeasible, IJ41 Fast operation as
pigment particles High efficiency may jam the bend CMOS actuator
compatible voltages and currents Standard MEMS processes can be
used Easy extension from single nozzles to pagewidth print heads
High CTE A material with a very High force can Requires special
IJ09, IJ17, IJ18, thermo- high coefficient of be generated material
(e.g. PTFE) IJ20, IJ21, IJ22, elastic thermal expansion Three
methods of Requires a PTFE IJ23, IJ24, IJ27, actuator (CTE) such as
PTFE deposition are deposition process, IJ28, IJ29, IJ30,
polytetrafluoroethylene under development: which is not yet IJ31,
IJ42, IJ43, (PTFE) is used. As chemical vapor standard in ULSI IJ44
high CTE materials deposition (CVD), fabs are usually non- spin
coating, and PTFE deposition conductive, a heater evaporation
cannot be followed fabricated from a PTFE is a with high conductive
material is candidate for low temperature (above incorporated. A 50
.mu.m dielectric constant 350.degree. C.) processing long PTFE bend
insulation in ULSI Pigmented inks actuator with Very low power may
be infeasible, polysilicon heater and consumption as pigment
particles 15 mW power input Many ink types may jam the bend can
provide 180 .mu.N can be used actuator force and 10 .mu.m Simple
planar deflection. Actuator fabrication motions include: Small chip
area Bend required for each Push actuator Buckle Fast operation
Rotate High efficiency CMOS compatible voltages and currents Easy
extension from single nozzles to pagewidth print heads Conduct-ive
A polymer with a high High force can Requires special IJ24 polymer
coefficient of thermal be generated materials thermo- expansion
(such as Very low power development (High elastic PTFE) is doped
with consumption CTE conductive actuator conducting substances Many
ink types polymer) to increase its can be used Requires a PTFE
conductivity to about 3 Simple planar deposition process, orders of
magnitude fabrication which is not yet below that of copper. Small
chip area standard in ULSI The conducting required for each fabs
polymer expands actuator PTFE deposition when resistively Fast
operation cannot be followed heated. High efficiency with high
Examples of CMOS temperature (above conducting dopants compatible
voltages 350.degree. C.) processing include: and currents
Evaporation and Carbon nanotubes Easy extension CVD deposition
Metal fibers from single nozzles techniques cannot Conductive
polymers to pagewidth print be used such as doped heads Pigmented
inks polythiophene may be infeasible, Carbon granules as pigment
particles may jam the bend actuator Shape A shape memory alloy High
force is Fatigue limits IJ26 memory such as TiNi (also available
(stresses maximum number alloy known as Nitinol- of hundreds of
MPa) of cycles Nickel Titanium alloy Large strain is Low strain
(1%) developed at the Naval available (more than is required to
extend Ordnance Laboratory) 3%) fatigue resistance is thermally
switched High corrosion Cycle rate between its weak resistance
limited by heat martensitic state and Simple removal its high
stiffness construction Requires unusual austenic state. The Easy
extension materials (TiNi) shape of the actuator from single
nozzles The latent heat of in its martensitic state to pagewidth
print transformation must is deformed relative to heads be provided
the austenic shape. Low voltage High current The shape change
operation operation causes ejection of a Requires pre- drop.
stressing to distort the martensitic state Linear Linear magnetic
Linear Magnetic Requires unusual IJ12 Magnetic actuators include
the actuators can be semiconductor Actuator Linear Induction
constructed with materials such as Actuator (LIA), Linear high
thrust, long soft magnetic alloys Permanent Magnet travel, and high
(e.g. CoNiFe) Synchronous Actuator efficiency using Some varieties
(LPMSA), Linear planar also require Reluctance semiconductor
permanent magnetic Synchronous Actuator fabrication materials such
as (LRSA), Linear techniques Neodymium iron Switched Reluctance
Long actuator boron (NdFeB) Actuator (LSRA), and travel is
available Requires the Linear Stepper Medium force is complex
multi- Actuator (LSA). available phase drive circuitry Low voltage
High current operation operation BASIC OPERATION MODE Actuator This
is the simplest Simple operation Drop repetition Thermal ink jet
directly mode of operation: the No external rate is usually
Piezoelectric ink pushes ink actuator directly fields required
limited to around 10 jet supplies sufficient Satellite drops kHz.
However, this IJ01, IJ02, IJ03, kinetic energy to expel can be
avoided if is not fundamental IJ04, IJ05, IJ06, the drop. The drop
drop velocity is less to the method, but is IJ07, IJ09, IJ11, must
have a sufficient than 4 m/s related to the refill IJ12, IJ14,
IJ16, velocity to overcome Can be efficient, method normally IJ20,
IJ22, IJ23, the surface tension. depending upon the used IJ24,
IJ25, IJ26, actuator used All of the drop IJ27, IJ28, IJ29, kinetic
energy must IJ30, IJ31, IJ32, be provided by the IJ33, IJ34, IJ35,
actuator IJ36, IJ37, IJ38, Satellite drops IJ39, IJ40, IJ41,
usually form if drop IJ42, IJ43, IJ44 velocity is greater than 4.5
m/s Proximity The drops to be Very simple print Requires close
Silverbrook, EP printed are selected by head fabrication can
proximity between 0771 658 A2 and some manner (e.g. be used the
print head and related patent thermally induced The drop the print
media or applications surface tension selection means transfer
roller reduction
of does not need to May require two pressurized ink). provide the
energy print heads printing Selected drops are required to separate
alternate rows of the separated from the ink the drop from the
image in the nozzle by nozzle Monolithic color contact with the
print print heads are medium or a transfer difficult roller.
Electro- The drops to be Very simple print Requires very
Silverbrook, EP static pull printed are selected by head
fabrication can high electrostatic 0771 658 A2 and on ink some
manner (e.g. be used field related patent thermally induced The
drop Electrostatic field applications surface tension selection
means for small nozzle Tone-Jet reduction of does not need to sizes
is above air pressurized ink). provide the energy breakdown
Selected drops are required to separate Electrostatic field
separated from the ink the drop from the may attract dust in the
nozzle by a nozzle strong electric field. Magnetic The drops to be
Very simple print Requires Silverbrook, EP pull on ink printed are
selected by head fabrication can magnetic ink 0771 658 A2 and some
manner (e.g. be used Ink colors other related patent thermally
induced The drop than black are applications surface tension
selection means difficult reduction of does not need to Requires
very pressurized ink). provide the energy high magnetic fields
Selected drops are required to separate separated from the ink the
drop from the in the nozzle by a nozzle strong magnetic field
acting on the magnetic ink. Shutter The actuator moves a High speed
(>50 Moving parts are IJ13, IJ17, IJ21 shutter to block ink kHz)
operation can required flow to the nozzle. The be achieved due to
Requires ink ink pressure is pulsed reduced refill time pressure
modulator at a multiple of the Drop timing can Friction and wear
drop ejection be very accurate must be considered frequency. The
actuator Stiction is energy can be very possible low Shuttered The
actuator moves a Actuators with Moving parts are IJ08, IJ15, IJ18,
grill shutter to block ink small travel can be required IJ19 flow
through a grill to used Requires ink the nozzle. The shutter
Actuators with pressure modulator movement need only small force
can be Friction and wear be equal to the width used must be
considered of the grill holes. High speed (>50 Stiction is kHz)
operation can possible be achieved Pulsed A pulsed magnetic
Extremely low Requires an IJ10 magnetic field attracts an `ink
energy operation is external pulsed pull on ink pusher` at the drop
possible magnetic field pusher ejection frequency. An No heat
Requires special actuator controls a dissipation materials for both
catch, which prevents problems the actuator and the the ink pusher
from ink pusher moving when a drop is Complex not to be ejected.
construction AUXILIARY MECHANISM (APPLIED TO ALL NOZZLES) None The
actuator directly Simplicity of Drop ejection Most ink jets, fires
the ink drop, and construction energy must be including there is no
external Simplicity of supplied by piezoelectric and field or other
operation individual nozzle thermal bubble. mechanism required.
Small physical actuator IJ01, IJ02, IJ03, size IJ04, IJ05, IJ07,
IJ09, IJ11, IJ12, IJ14, IJ20, IJ22, IJ23, IJ24, IJ25, IJ26, IJ27,
IJ28, IJ29, IJ30, IJ31, IJ32, IJ33, IJ34, IJ35, IJ36, IJ37, IJ38,
IJ39, IJ40, IJ41, IJ42, IJ43, IJ44 Oscillating The ink pressure
Oscillating ink Requires external Silverbrook, EP ink pressure
oscillates, providing pressure can provide ink pressure 0771 658 A2
and (including much of the drop a refill pulse, oscillator related
patent acoustic ejection energy. The allowing higher Ink pressure
applications stimula- actuator selects which operating speed phase
and amplitude IJ08, IJ13, IJ15, tion) drops are to be fired The
actuators must be carefully IJ17, IJ18, IJ19, by selectively may
operate with controlled IJ21 blocking or enabling much lower energy
Acoustic nozzles. The ink Acoustic lenses reflections in the ink
pressure oscillation can be used to focus chamber must be may be
achieved by the sound on the designed for vibrating the print
nozzles head, or preferably by an actuator in the ink supply. Media
The print head is Low power Precision Silverbrook, EP proximity
placed in close High accuracy assembly required 0771 658 A2 and
proximity to the print Simple print head Paper fibers may related
patent medium. Selected construction cause problems applications
drops protrude from Cannot print on the print head further rough
substrates than unselected drops, and contact the print medium. The
drop soaks into the medium fast enough to cause drop separation.
Transfer Drops are printed to a High accuracy Bulky Silverbrook, EP
roller transfer roller instead Wide range of Expensive 0771 658 A2
and of straight to the print print substrates can Complex related
patent medium. A transfer be used construction applications roller
can also be used Ink can be dried Tektronix hot for proximity drop
on the transfer roller melt piezoelectric separation. ink jet Any
of the IJ series Electro- An electric field is Low power Field
strength Silverbrook, EP static used to accelerate Simple print
head required for 0771 658 A2 and selected drops towards
construction separation of small related patent the print medium.
drops is near or applications above air Tone-Jet breakdown Direct A
magnetic field is Low power Requires Silverbrook, EP magnetic used
to accelerate Simple print head magnetic ink 0771 658 A2 and field
selected drops of construction Requires strong related patent
magnetic ink towards magnetic field applications the print medium.
Cross The print head is Does not require Requires external IJ06,
IJ16 magnetic placed in a constant magnetic materials magnet field
magnetic field. The to be integrated in Current densities Lorenz
force in a the print head may be high, current carrying wire
manufacturing resulting in is used to move the process
electromigration actuator. problems Pulsed A pulsed magnetic Very
low power Complex print IJ10 magnetic field is used to operation is
possible head construction field cyclically attract a Small print
head Magnetic paddle, which pushes size materials required in on
the ink. A small print head actuator moves a catch, which
selectively prevents the paddle from moving. ACTUATOR AMPLIFICATION
OR MODIFICATION METHOD None No actuator Operational Many actuator
Thermal Bubble mechanical simplicity mechanisms have Ink jet
amplification is used. insufficient travel, IJ01, IJ02, IJ06, The
actuator directly or insufficient force, IJ07, IJ16, IJ25, drives
the drop to efficiently drive IJ26 ejection process. the drop
ejection process Differential An actuator material Provides greater
High stresses are Piezoelectric expansion expands more on one
travel in a reduced involved IJ03, IJ09, IJ17, bend side than on
the other. print head area Care must be IJ18, IJ19, IJ20, actuator
The expansion may be taken that the IJ21, IJ22, IJ23, thermal,
piezoelectric, materials do not IJ24, IJ27, IJ29, magnetostrictive,
or delaminate IJ30, IJ31, IJ32, other mechanism. The Residual bend
IJ33, IJ34, IJ35, bend actuator converts resulting from high IJ36,
IJ37, IJ38, a high force low travel temperature or high IJ39, IJ42,
IJ43, actuator mechanism to stress during IJ44 high travel, lower
formation force mechanism. Transient A trilayer bend Very good High
stresses are IJ40, IJ41 bend actuator where the two temperature
stability involved actuator outside layers are High speed, as a
Care must be identical. This cancels new drop can be taken that the
bend due to ambient fired before heat materials do not temperature
and dissipates delaminate residual stress. The Cancels residual
actuator only responds stress of formation to transient heating of
one side or the other. Reverse The actuator loads a Better coupling
Fabrication IJ05, IJ11 spring spring. When the to the ink
complexity actuator is turned off, High stress in the the spring
releases. spring This can reverse the force/distance curve of the
actuator to make it compatible with the force/time requirements of
the drop ejection. Actuator A series of thin Increased travel
Increased Some stack actuators are stacked. Reduced drive
fabrication piezoelectric ink jets This can be voltage complexity
IJ04 appropriate where Increased actuators require high possibility
of short electric field strength, circuits due to such as
electrostatic pinholes and piezoelectric actuators. Multiple
Multiple smaller Increases the Actuator forces IJ12, IJ13, IJ18,
actuators actuators are used force available from may not add IJ20,
IJ22, IJ28, simultaneously to an actuator linearly, reducing IJ42,
IJ43 move the ink. Each Multiple efficiency actuator need provide
actuators can be only a portion of the positioned to control force
required. ink flow accurately Linear A linear spring is used
Matches low Requires print IJ15 Spring to transform a motion travel
actuator with head area for the with small travel and higher travel
spring high force into a requirements longer travel, lower
Non-contact force motion. method of motion transformation Coiled A
bend actuator is Increases travel Generally IJ17, IJ21, IJ34,
actuator coiled to provide Reduces chip restricted to planar IJ35
greater travel in a area implementations reduced chip area. Planar
due to extreme implementations are fabrication difficulty
relatively easy to in other orientations. fabricate. Flexure A bend
actuator has a Simple means of Care must be IJ10, IJ19, IJ33 bend
small region near the increasing travel of taken not to exceed
actuator fixture point, which a bend actuator the elastic limit in
flexes much more the flexure area readily than the Stress remainder
of the distribution is very actuator. The actuator uneven flexing
is effectively Difficult to converted from an accurately model even
coiling to an with finite element angular bend, resulting analysis
in greater travel of the actuator tip. Catch The actuator controls
a Very low Complex IJ10 small catch. The catch actuator energy
construction either enables or Very small Requires external
disables movement of actuator size force an ink pusher that is
Unsuitable for controlled in a bulk pigmented inks manner. Gears
Gears can be used to Low force, low Moving parts are IJ13 increase
travel at the travel actuators can required expense of duration. be
used Several actuator Circular gears, rack Can be fabricated cycles
are required and pinion, ratchets, using standard More complex and
other gearing surface MEMS drive electronics methods can be used.
processes Complex construction Friction, friction, and wear are
possible Buckle plate A buckle plate can be Very fast Must stay
within S. Hirata et al, used to change a slow movement elastic
limits of the "An Ink-jet Head actuator into a fast achievable
materials for long Using Diaphragm motion. It can also device life
Microactuator", convert a high force, High stresses Proc. IEEE
MEMS, low travel actuator involved Feb. 1996, pp 418- into a high
travel, Generally high 423. medium force motion. power requirement
IJ18, IJ27 Tapered A tapered magnetic Linearizes the Complex IJ14
magnetic pole can increase magnetic construction pole travel at the
expense force/distance curve of force. Lever A lever and fulcrum is
Matches low High stress IJ32, IJ36, IJ37 used to transform a travel
actuator with around the fulcrum motion with small higher travel
travel and high force requirements into a motion with Fulcrum area
has longer travel and no linear movement, lower force. The lever
and can be used for can also reverse the a fluid seal direction of
travel. Rotary The actuator is High mechanical Complex IJ28
impeller connected to a rotary advantage construction impeller. A
small The ratio of force Unsuitable for angular deflection of to
travel of the pigmented inks the actuator results in actuator can
be a rotation of the matched to the impeller vanes, which nozzle
requirements push the ink against by varying the stationary vanes
and number of impeller out of the nozzle. vanes Acoustic A
refractive or No moving parts Large area 1993 Hadimioglu lens
diffractive (e.g. zone required et al, EUP 550,192 plate) acoustic
lens is Only relevant for 1993 Elrod et al, used to concentrate
acoustic ink jets EUP 572,220 sound waves. Sharp A sharp point is
used Simple Difficult to Tone-jet conductive to concentrate an
construction fabricate using point electrostatic field. standard
VLSI processes for a surface ejecting ink- jet Only relevant for
electrostatic ink jets ACTUATOR MOTION Volume The volume of the
Simple High energy is Hewlett-Packard expansion actuator changes,
construction in the typically required to Thermal Ink jet pushing
the ink in all case of thermal ink achieve volume Canon Bubblejet
directions. jet expansion. This leads to thermal stress,
cavitation, and kogation in thermal ink jet implementations Linear,
The actuator moves in Efficient High fabrication IJ01, IJ02, IJ04,
normal to a direction normal to coupling to ink complexity may be
IJ07, IJ11, IJ14 chip surface the print head surface. drops ejected
required to achieve The nozzle is typically normal to the
perpendicular in the line of surface motion movement. Parallel to
The actuator moves Suitable for Fabrication IJ12, IJ13, IJ15, chip
surface parallel to the print planar fabrication complexity IJ33, ,
IJ34, IJ35, head surface. Drop Friction IJ36 ejection may still be
Stiction normal to the surface. Membrane An actuator with a The
effective Fabrication 1982 Howkins push high force but small area
of the actuator complexity U.S. Pat. No. area is used to push a
becomes the Actuator size 4,459,601 stiff membrane that is membrane
area Difficulty of in contact with the ink. integration in a VLSI
process Rotary The actuator causes Rotary levers Device IJ05, IJ08,
IJ13, the rotation of some may be used to complexity IJ28 element,
such a grill or increase travel May have impeller Small chip area
friction at a pivot requirements point Bend The actuator bends A
very small Requires the 1970 Kyser et al when energized. This
change in actuator to be made U.S. Pat. No. may be due to
dimensions can be from at least two 3,946,398 differential thermal
converted to a large distinct layers, or to 1973 Stemme expansion,
motion. have a thermal U.S. Pat. No. piezoelectric difference
across the 3,747,120 expansion, actuator IJ03, IJ09, IJ10,
magnetostriction, or IJ19, IJ23, IJ24, other form of relative IJ25,
IJ29, IJ30, dimensional change. IJ31, IJ33, IJ34, IJ35 Swivel The
actuator swivels Allows operation Inefficient IJ06 around a central
pivot. where the net linear coupling to the ink This motion is
suitable force on the paddle motion where there are is zero
opposite forces Small chip area applied to opposite requirements
sides of the paddle, e.g. Lorenz force. Straighten The actuator is
Can be used with Requires careful IJ26, IJ32 normally bent, and
shape memory balance of stresses straightens when alloys where the
to ensure that the energized. austenic phase is quiescent bend is
planar accurate Double The actuator bends in One actuator can
Difficult to make IJ36, IJ37, IJ38 bend one direction when be used
to power the drops ejected by one element is two nozzles. both bend
directions energized, and bends Reduced chip identical. the other
way when size. A small another element is Not sensitive to
efficiency loss energized. ambient temperature compared to
equivalent single bend actuators. Shear Energizing the Can increase
the Not readily 1985 Fishbeck actuator causes a shear effective
travel of applicable to other U.S. Pat. No. motion in the actuator
piezoelectric actuator 4,584,590 material. actuators mechanisms
Radial con- The actuator squeezes Relatively easy High force 1970
Zoltan striction an ink reservoir, to fabricate single required
U.S. Pat. No. forcing ink from a nozzles from glass Inefficient
3,683,212 constricted nozzle. tubing as Difficult to macroscopic
integrate with VLSI structures processes Coil/uncoil A coiled
actuator Easy to fabricate Difficult to IJ17, IJ21, IJ34, uncoils
or coils more as a planar VLSI fabricate for non- IJ35 tightly. The
motion of process planar devices the free end of the Small area
Poor out-of-plane actuator ejects the ink. required, therefore
stiffness low cost Bow The actuator bows (or Can increase the
Maximum travel IJ16, IJ18, IJ27 buckles) in the middle speed of
travel is constrained when energized. Mechanically High force rigid
required Push-Pull Two actuators control The structure is Not
readily IJ18 a shutter. One actuator pinned at both ends, suitable
for ink jets pulls the shutter, and so has a high out-of- which
directly push the other pushes it. plane rigidity the ink Curl A
set of actuators curl Good fluid flow Design IJ20, IJ42 inwards
inwards to reduce the to the region behind complexity volume of ink
that the actuator they enclose. increases efficiency Curl A set of
actuators curl Relatively simple Relatively large IJ43 outwards
outwards, pressurizing construction chip area ink in a chamber
surrounding the actuators, and expelling ink from a nozzle in the
chamber. Iris Multiple vanes enclose High efficiency High
fabrication IJ22 a volume of ink. These Small chip area complexity
simultaneously rotate, Not suitable for reducing the volume
pigmented inks between the vanes. Acoustic The actuator vibrates
The actuator can Large area 1993 Hadimioglu vibration at a high
frequency. be physically distant required for et al, EUP 550,192
from the ink efficient operation 1993 Elrod et al, at useful
frequencies EUP 572,220 Acoustic coupling and crosstalk Complex
drive circuitry Poor control of drop volume and position None In
various ink jet No moving parts Various other Silverbrook, EP
designs the actuator tradeoffs are 0771 658 A2 and does not move.
required to related patent eliminate moving applications parts
Tone-jet NOZZLE REFILL METHOD Surface This is the normal way
Fabrication Low speed Thermal ink jet tension that ink jets are
simplicity Surface tension Piezoelectric ink refilled. After the
Operational force relatively jet actuator is energized, simplicity
small compared to IJ01-IJ07, IJ10- it typically returns actuator
force IJ14, IJ16, IJ20, rapidly to its normal Long refill time
IJ22-IJ45 position. This rapid usually dominates return sucks in
air the total repetition through the nozzle rate opening. The ink
surface tension at the nozzle then exerts a small force restoring
the meniscus to a minimum area. This force refills the nozzle.
Shuttered Ink to the nozzle High speed Requires IJ08, IJ13, IJ15,
oscillating chamber is provided at Low actuator common ink IJ17,
IJ18, IJ19, ink pressure a pressure that energy, as the pressure
oscillator IJ21 oscillates at twice the actuator need only May not
be drop ejection open or close the suitable for frequency. When a
shutter, instead of pigmented inks drop is to be ejected, ejecting
the ink drop the shutter is opened for 3 half cycles: drop
ejection, actuator return, and refill. The shutter is then closed
to prevent the nozzle chamber emptying during the next negative
pressure cycle. Refill After the main High speed, as Requires two
IJ09 actuator actuator has ejected a the nozzle is independent drop
a second (refill) actively refilled actuators per nozzle actuator
is energized. The refill actuator pushes ink into the nozzle
chamber. The refill actuator returns slowly, to prevent its return
from emptying the chamber again. Positive ink The ink is held a
slight High refill rate, Surface spill Silverbrook, EP pressure
positive pressure. therefore a high must be prevented 0771 658 A2
and After the ink drop is drop repetition rate Highly related
patent ejected, the nozzle is possible hydrophobic print
applications chamber fills quickly head surfaces are Alternative
for:, as surface tension and required IJ01-1107, IJ10-IJ14, ink
pressure both IJ16, IJ20, IJ22-IJ45 operate to refill the nozzle.
METHOD OF RESTRICTING BACK-FLOW THROUGH INLET Long inlet The ink
inlet channel Design simplicity Restricts refill Thermal ink jet
channel to the nozzle chamber Operational rate Piezoelectric ink is
made long and simplicity May result in a jet relatively narrow,
Reduces relatively large chip IJ42, IJ43 relying on viscous
crosstalk area drag to reduce inlet Only partially back-flow.
effective Positive ink The ink is under a Drop selection Requires a
Silverbrook, EP pressure positive pressure, so and separation
method (such as a 0771 658 A2 and that in the quiescent forces can
be nozzle rim or related patent state some of the ink reduced
effective applications drop already protrudes Fast refill time
hydrophobizing, or Possible from the nozzle. both) to prevent
operation of the This reduces the flooding of the following: IJ01-
pressure in the nozzle ejection surface of IJ07, IJ09-IJ12, chamber
which is the print head. IJ14, IJ16, IJ20, required to eject a
IJ22, , IJ23-IJ34, certain volume of ink. IJ36-IJ41, IJ44 The
reduction in chamber pressure results in a reduction in ink pushed
out through the inlet. Baffle One or more baffles The refill rate
is Design HP Thermal Ink are placed in the inlet not as restricted
as complexity Jet ink flow. When the the long inlet May increase
Tektronix actuator is energized, method. fabrication piezoelectric
ink jet the rapid ink Reduces complexity (e.g. movement creates
crosstalk Tektronix hot melt eddies which restrict Piezoelectric
print the flow through the heads). inlet. The slower refill process
is unrestricted, and does not result in eddies. Flexible flap In
this method recently Significantly Not applicable to Canon
restricts disclosed by Canon, reduces back-flow most ink jet inlet
the expanding actuator for edge-shooter configurations (bubble)
pushes on a thermal ink jet Increased flexible flap that devices
fabrication restricts the inlet. complexity Inelastic deformation
of polymer flap results in creep over extended use Inlet filter A
filter is located Additional Restricts refill IJ04, IJ12, IJ24,
between the ink inlet advantage of ink rate IJ27, IJ29, IJ30 and
the nozzle filtration May result in chamber. The filter Ink filter
may be complex has a multitude of fabricated with no construction
small holes or slots, additional process restricting ink flow.
steps The filter also removes particles which may block the nozzle.
Small inlet The ink inlet channel Design simplicity Restricts
refill IJ02, IJ37, IJ44 compared to the nozzle chamber rate to
nozzle has a substantially May result in a smaller cross section
relatively large chip than that of the nozzle, area resulting in
easier ink Only partially egress out of the effective nozzle than
out of the inlet. Inlet shutter A secondary actuator Increases
speed Requires separate IJ09 controls the position of of the
ink-jet print refill actuator and a shutter, closing off head
operation drive circuit the ink inlet when the main actuator is
energized. The inlet is The method avoids the Back-flow Requires
careful IJ01, IJ03, IJ05, located problem of inlet back- problem is
design to minimize IJ06, IJ07, IJ10, behind the flow by arranging
the eliminated the negative IJ11, IJ14, IJ16, ink-pushing
ink-pushing surface of pressure behind the IJ22, IJ23, IJ25,
surface the actuator between paddle IJ28, IJ31, IJ32, the inlet and
the IJ33, IJ34, IJ35, nozzle. IJ36, IJ39, IJ40, IJ41 Part of the
The actuator and a Significant Small increase in IJ07, IJ20, IJ26,
actuator wall of the ink reductions in back- fabrication IJ38 moves
to chamber are arranged flow can be complexity shut off the so that
the motion of achieved inlet the actuator closes off Compact
designs the inlet. possible Nozzle In some configurations Ink
back-flow None related to Silverbrook, EP actuator of ink jet,
there is no problem is ink back-flow on 0771 658 A2 and does not
expansion or eliminated actuation related patent result in ink
movement of an applications back-flow actuator which may Valve-jet
cause ink back-flow Tone-jet through the inlet. NOZZLE CLEARING
METHOD Normal All of the nozzles are No added May not be Most ink
jet nozzle firing fired periodically, complexity on the sufficient
to systems before the ink has a print head displace dried ink IJ01,
IJ02, IJ03, chance to dry. When IJ04, IJ05, IJ06, not in use the
nozzles IJ07, IJ09, IJ10, are sealed (capped) IJ11, IJ12, IJ14,
against air. IJ16, IJ20, IJ22, The nozzle firing is IJ23, IJ24,
IJ25, usually performed IJ26, IJ27, IJ28, during a special IJ29,
IJ30, IJ31, clearing cycle, after IJ32, IJ33, IJ34, first moving
the print IJ36, IJ37, IJ38, head to a cleaning IJ39, IJ40,, IJ41,
station. IJ42, IJ43, IJ44,, IJ45 Extra In systems which heat Can be
highly Requires higher Silverbrook, EP power to the ink, but do not
boil effective if the drive voltage for 0771 658 A2 and ink heater
it under normal heater is adjacent to clearing related patent
situations, nozzle the nozzle May require applications clearing can
be larger drive achieved by over- transistors powering the heater
and boiling ink at the nozzle. Rapid The actuator is fired in Does
not require Effectiveness May be used success-ion rapid succession.
In extra drive circuits depends with: IJ01, IJ02, of actuator some
configurations, on the print head substantially upon IJ03, IJ04,
IJ05, pulses this may cause heat Can be readily the configuration
of IJ06, IJ07, IJ09, build-up at the nozzle controlled and the ink
jet nozzle IJ10, IJ11, IJ14, which boils the ink, initiated by
digital IJ16, IJ20, IJ22, clearing the nozzle. In logic IJ23, IJ24,
IJ25, other situations, it may IJ27, IJ28, IJ29, cause sufficient
IJ30, IJ31, IJ32, vibrations to dislodge IJ33, IJ34, IJ36, clogged
nozzles. IJ37, IJ38, IJ39, IJ40, IJ41, IJ42, IJ43, IJ44, IJ45 Extra
Where an actuator is A simple Not suitable May be used power to not
normally driven to solution where where there is a with: IJ03,
IJ09, ink pushing the limit of its motion, applicable hard limit to
IJ16, IJ20, IJ23, actuator nozzle clearing may be actuator movement
IJ24, IJ25, IJ27, assisted by providing IJ29, IJ30, IJ31, an
enhanced drive IJ32, IJ39, IJ40, signal to the actuator. IJ41,
IJ42, IJ43, IJ44, IJ45 Acoustic An ultrasonic wave is A high nozzle
High IJ08, IJ13, IJ15, resonance applied to the ink clearing
capability implementation cost IJ17, IJ18, IJ19, chamber. This wave
is can be achieved if system does not IJ21 of an appropriate May be
already include an amplitude and implemented at very acoustic
actuator frequency to cause low cost in systems sufficient force at
the which already nozzle to clear include acoustic blockages. This
is actuators easiest to achieve if the ultrasonic wave is at a
resonant frequency of the ink cavity. Nozzle A microfabricated Can
clear Accurate Silverbrook, EP clearing plate is pushed against
severely clogged mechanical 0771 658 A2 and plate the nozzles. The
plate nozzles alignment is related patent has a post for every
required applications nozzle. A post moves Moving parts are through
each nozzle, required displacing dried ink. There is risk of damage
to the nozzles Accurate fabrication is required Ink The pressure of
the ink May be effective Requires May be used pressure is
temporarily where other pressure pump or with all IJ series ink
pulse increased so that ink methods cannot be other pressure jets
streams from all of the used actuator nozzles. This may be
Expensive used in conjunction Wasteful of ink with actuator
energizing. Print head A flexible `blade` is Effective for
Difficult to use if Many ink jet wiper wiped across the print
planar print head print head surface is systems head surface. The
surfaces non-planar or very blade is usually Low cost fragile
fabricated from a Requires flexible polymer, e.g. mechanical parts
rubber or synthetic Blade can wear elastomer. out in high volume
print systems Separate A separate heater is Can be effective
Fabrication Can be used with ink boiling provided at the nozzle
where other nozzle complexity many IJ series ink heater although
the normal clearing methods jets drop e-ection cannot be used
mechanism does not Can be require it. The heaters implemented at no
do not require additional cost in individual drive some ink jet
circuits, as many configurations nozzles can be cleared
simultaneously, and no imaging is required. NOZZLE PLATE
CONSTRUCTION Electro- A nozzle plate is Fabrication High Hewlett
Packard formed separately fabricated simplicity temperatures and
Thermal Ink jet nickel from electroformed pressures are nickel, and
bonded to required to bond the print head chip. nozzle plate
Minimum thickness constraints Differential thermal expansion Laser
Individual nozzle No masks Each hole must Canon Bubblejet ablated
or holes are ablated by an required be individually 1988 Sercel et
drilled intense UV laser in a Can be quite fast formed al., SPLE,
Vol. 998 polymer nozzle plate, which is Some control Special
Excimer Beam typically a polymer over nozzle profile equipment
required Applications, pp. such as polyimide or is possible Slow
where there 76-83 polysulphone Equipment are many thousands 1993
Watanabe required is relatively of nozzles per print et al., U.S.
Pat. No. low cost head 5,208,604 May produce thin burrs at exit
holes Silicon A separate nozzle High accuracy is Two part K. Bean,
IEEE micro- plate is attainable construction Transactions on
machined micromachined from High cost Electron Devices, single
crystal silicon, Requires Vol. ED-25, No. 10, and bonded to the
precision alignment 1978, pp IJ85-IJ95 print head wafer. Nozzles
may be Xerox 1990 clogged by adhesive Hawkins et al., U.S. Pat. No.
4,899,181 Glass Fine glass capillaries No expensive Very small 1970
Zoltan capillaries are drawn from glass equipment required nozzle
sizes are U.S. Pat. No. tubing. This method Simple to make
difficult to form 3,683,212 has been used for single nozzles Not
suited for making individual mass production nozzles, but is
difficult to use for bulk manufacturing of print heads with
thousands of
nozzles. Monolithic, The nozzle plate is High accuracy Requires
Silverbrook, EP surface deposited as a layer (<1 .mu.m)
sacrificial layer 0771 658 A2 and micro- using standard VLSI
Monolithic under the nozzle related patent machined deposition
techniques. Low cost plate to form the applications using VLSI
Nozzles are etched in Existing nozzle chamber IJ01, IJ02, IJ04,
litho- the nozzle plate using processes can be Surface may be IJ11,
IJ12, IJ17, graphic VLSI lithography and used fragile to the touch
IJ18, IJ20, IJ22, processes etching. IJ24, IJ27, IJ28, IJ29, IJ30,
IJ31, IJ32, IJ33, IJ34, IJ36, IJ37, IJ38, IJ39, IJ40, IJ41, IJ42,
IJ43, IJ44 Monolithic, The nozzle plate is a High accuracy Requires
long IJ03, IJ05, IJ06, etched buried etch stop in the (<1 .mu.m)
etch times IJ07, IJ08, IJ09, through wafer. Nozzle Monolithic
Requires a IJ10, IJ13, IJ14, substrate chambers are etched in Low
cost support wafer IJ15, IJ16, IJ19, the front of the wafer, No
differential IJ21, IJ23, IJ25, and the wafer is expansion IJ26
thinned from the back side. Nozzles are then etched in the etch
stop layer. No nozzle Various methods have No nozzles to Difficult
to Ricoh 1995 plate been tried to eliminate become clogged control
drop Sekiya et al the nozzles entirely, to position accurately U.S.
Pat. No. prevent nozzle Crosstalk 5,412,413 clogging. These
problems 1993 Hadimioglu include thermal bubble et al EUP 550,192
mechanisms and 1993 Elrod et al acoustic lens EUP 572,220
mechanisms Trough Each drop ejector has Reduced Drop firing IJ35 a
trough through manufacturing direction is sensitive which a paddle
moves, complexity to wicking. There is no nozzle Monolithic plate.
Nozzle slit The elimination of No nozzles to Difficult to 1989
Saito et al instead of nozzle holes and become clogged control drop
U.S. Pat. No. individual replacement by a slit position accurately
4,799,068 nozzles encompassing many Crosstalk actuator positions
problems reduces nozzle clogging, but increases crosstalk due to
ink surface waves DROP EJECTION DIRECTION Edge Ink flow is along
the Simple Nozzles limited Canon Bubblejet (`edge surface of the
chip, construction to edge 1979 Endo et al GB shooter`) and ink
drops are No silicon High resolution patent 2,007,162 ejected from
the chip etching required is difficult Xerox heater-in- edge. Good
heat Fast color pit 1990 Hawkins et sinking via substrate printing
requires al U.S. Pat. No. Mechanically one print head per 4,899,181
strong color Tone-jet Ease of chip handing Surface Ink flow is
along the No bulk silicon Maximum ink Hewlett-Packard (`roof
surface of the chip, etching required flow is severely TIJ 1982
Vaught et shooter`) and ink drops are Silicon can make restricted
al U.S. Pat. No. ejected from the chip an effective heat 4,490,728
surface, normal to the sink IJ02, IJ11, IJ12, plane of the chip.
Mechanical IJ20, IJ22 strength Through Ink flow is through the High
ink flow Requires bulk Silverbrook, EP chip, chip, and ink drops
are Suitable for silicon etching 0771 658 A2 and forward ejected
from the front pagewidth print related patent (`up surface of the
chip. heads applications shooter`) High nozzle IJ04, IJ17, IJ18,
packing density IJ24, IJ27-IJ45 therefore low manufacturing cost
Through Ink flow is through the High ink flow Requires wafer IJ01,
IJ03, IJ05, chip, chip, and ink drops are Suitable for thinning
IJ06, IJ07, IJ08, reverse ejected from the rear pagewidth print
Requires special IJ09, IJ10, IJ13, (`down surface of the chip.
heads handling during IJ14, IJ15, IJ16, shooter`) High nozzle
manufacture IJ19, IJ21, IJ23, packing density IJ25, IJ26 therefore
low manufacturing cost Through Ink flow is through the Suitable for
Pagewidth print Epson Stylus actuator actuator, which is not
piezoelectric print heads require Tektronix hot fabricated as part
of heads several thousand melt piezoelectric the same substrate as
connections to drive ink jets the drive transistors. circuits
Cannot be manufactured in standard CMOS fabs Complex assembly
required INK TYPE Aqueous, Water based ink which Enviromnentally
Slow drying Most existing ink dye typically contains: friendly
Corrosive jets water, dye, surfactant, No odor Bleeds on paper All
IJ series ink humectant, and May jets biocide. strikethrough
Silverbrook, EP Modem ink dyes have Cockles paper 0771 658 A2 and
high water-fastness, related patent light fastness applications
Aqueous, Water based ink which Environmentally Slow drying IJ02,
IJ04, IJ21, pigment typically contains: friendly Corrosive IJ26,
IJ27, IJ30 water, pigment, No odor Pigment may Silverbrook, EP
surfactant, humectant, Reduced bleed clog nozzles 0771 658 A2 and
and biocide. Reduced wicking Pigment may related patent Pigments
have an Reduced clog actuator applications advantage in reduced
strikethrough mechanisms Piezoelectric ink- bleed, wicking and
Cockles paper jets strikethrough. Thermal ink jets (with
significant restrictions) Methyl MEK is a highly Very fast drying
Odorous All IJ series ink Ethyl volatile solvent used Prints on
various Flammable jets Ketone for industrial printing substrates
such as (MEK) on difficult surfaces metals and plastics such as
aluminum cans. Alcohol Alcohol based inks Fast drying Slight odor
All IJ series ink (ethanol, 2- can be used where the Operates at
sub- Flammable jets butanol, printer must operate at freezing and
others) temperatures below temperatures the freezing point of
Reduced paper water. An example of cockle this is in-camera Low
cost consumer photographic printing. Phase The ink is solid at No
drying time- High viscosity Tektronix hot change room temperature,
and ink instantly freezes Printed ink melt piezoelectric (hot melt)
is melted in the print on the print medium typically has a ink jets
head before jetting. Almost any print `waxy` feel 1989 Nowak Hot
melt inks are medium can be used Printed pages U.S. Pat. No.
usually wax based, No paper cockle may `block` 4,820,346 with a
melting point occurs Ink temperature All IJ series ink around
80.degree. C. After No wicking may be above the jets jetting the
ink freezes occurs curie point of almost instantly upon No bleed
occurs permanent magnets contacting the print No strikethrough Ink
heaters medium or a transfer occurs consume power roller. Long
warm-up time Oil Oil based inks are High solubility High viscosity:
All IJ series ink extensively used in medium for some this is a
significant jets offset printing. They dyes limitation for use in
have advantages in Does not cockle ink jets, which improved paper
usually require a characteristics on Does not wick low viscosity.
Some paper (especially no through paper short chain and wicking or
cockle). multi-branched oils Oil soluble dies and have a
sufficiently pigments are required. low viscosity. Slow drying
Micro- A microemulsion is a Stops ink bleed Viscosity higher All IJ
series ink emulsion stable, self forming High dye than water jets
emulsion of oil, water, solubility Cost is slightly and surfactant.
The Water, oil, and higher than water characteristic drop size
amphiphilic soluble based ink is less than 100 nm, dies can be used
High surfactant and is determined by Can stabilize concentration
the preferred curvature pigment required (around of the surfactant.
suspensions 5%)
* * * * *